Hepatopulmonary syndrome in candidates for liver transplantation

Cardiopulmonary complications in chronic liver disease

Patients with cirrhosis and portal hypertension exhibit characteristic cardiovascular and pulmonary hemodynamic changes. A vasodilatatory state and a hyperdynamic circulation affecting the cardiac and pulmonary functions dominate the circulation. The recently defined cirrhotic cardiomyopathy may affect systolic and diastolic functions, and imply electromechanical abnormalities. In addition, the baroreceptor function and regulation of the circulatory homoeostasis is impaired. Pulmonary dysfunction involves diffusing abnormalities with the development of the hepatopulmonary syndrome and portopulmonary hypertension in some patients. Recent research has focused on the assertion that the hemodynamic and neurohumoral dysregulation are of major importance for the development of the cardiovascular and pulmonary complications in cirrhosis. This aspect is important to take into account in the management of these patients.

Effect of transjugular intrahepatic portosystemic shunt on pulmonary gas exchange in patients with portal hypertension and hepatopulmonary syndrome

AIM: To assess the impact of transjugular intrahepatic portosystemic shunt (TIPS) on pulmonary gas exchange and to evaluate the use of TIPS for the treatment of hepatopulmonary syndrome ( HPS ).

METHODS: Seven patients, three of them with advanced HPS, in whom detailed pulmonary function tests were performed before and after TIPS placement at the University of Alabama Hospital and at the Hospital Clinic, Barcelona, were considered.

RESULTS: TIPS patency was confirmed by hemodynamic evaluation. No changes in arterial blood gases were observed in the overall subset of patients. Transient arterial oxygenation improvement was observed in only one HPS patient, early after TIPS, but this was not sustained 4 mo later.

CONCLUSION: TIPS neither improved nor worsened pulmonary gas exchange in patients with portal hypertension. This data does not support the use of TIPS as a specific treatment for HPS. However, it does reinforce the view that TIPS can be safely performed for the treatment of other complications of portal hypertension in patients with HPS.

Recent advances in hepatopulmonary syndrome

Hepatopulmonary syndrome is defined as the clinical triad of advanced liver disease, arterial deoxygenation and intrapulmonary vascular dilatation. Its pathogenesis is not completely understood. Excessive pulmonary nitric oxide production seems to be one of the factors that contribute to the intrapulmonary vascular dilatation. Other mediators such as endothelin-1 and the heme oxygenase-1/carbon monoxide system have recently been found to be important contributors. The major clinical manifestations are arterial hypoxemia, clubbed fingers and spider nevi. Orthodeoxia is the characteristic clinical feature. Contrast-enhanced echocardiography is the preferred screening test. 99mTechnetium macroaggregated albumin (Tc-99m MAA) lung perfusion scan can further specify the diagnosis of hepatopulmonary syndrome and quantify the magnitude of shunting. No clearly effective medical treatments have been found. Although liver transplantation seems feasible to reverse this situation, it is associated with increased postoperative morbidity and mortality. A preoperative arterial oxygen tension of 50 mmHg or less and Tc-99m MAA shunt fractions of 20% or more are strong predictors of postoperative mortality that can be used to stratify patients with better outcome.

Hepatopulmonary syndrome

The hepatopulmonary syndrome is an increasingly important vascular complication of cirrhosis where microvascular dilatation impairs arterial oxygenation in the setting of liver disease. This syndrome is identified in as many as 20% of patients evaluated for liver transplantation and results in increased mortality. No clearly effective medical therapies are available, and liver transplantation is the only established treatment. Pathophysiologic insights obtained from experimental models may lead to the development of novel and effective medical treatments.

Arterial hypoxemia and intrapulmonary vasodilatation in rat models of portal hypertension

BACKGROUND

Rats with chronic bile duct ligation (CBDL) and portal vein ligation (PVL) are used as models of portal hypertension. CBDL rats show hypoxemia with intrapulmonary vasodilatation (IPVD), and are recognized as a model of hepatopulmonary syndrome (HPS), while PVL rats are normoxemic. We investigated the differences in arterial oxygenation between these models, and the key factors leading to HPS.

METHODS

Forty-eight Sprague-Dawley rats were prepared as CBDL or PVL models, or as Sham rats. Arterial oxygenation, hemodynamics (reference sample method), and IPVD were simultaneously evaluated in conscious and unrestrained animals, using (141)Ce- or (113)Sn-labeled microspheres (15 microm in diameter), respectively. Endothelin-1 (ET-1) and nitrate/nitrite (end products of nitric oxide; NOx) production by the lung tissue (increment across the lungs) was also determined.

RESULTS

The extent of IPVD was similar in both models, but hypoxemia was only observed in CBDL rats. The ET-1 level and the increment in NOx were significantly increased in CBDL rats, and the increment was directly correlated with impairment of oxygenation. Blood flow through the bronchial arteries (anatomical shunting) was increased in CBDL rats, reaching more than three times the level in PVL rats or Sham rats.

CONCLUSIONS

These results support the hypothesis that NO derived from the lung tissues contributes to hypoxemia, and IPVD appears to be a prerequisite for impaired oxygenation. The considerable increase of anatomical shunting may potentially contribute to impaired oxygenation in CBDL rats.

Síndrome hepatopulmonar: patogenia, diagnóstico e tratamento

RACIONAL: A síndrome hepatopulmonar é caracterizada por tríade clínica que consiste em: 1) doença hepática e/ou hipertensão portal, 2) dilatações vasculares intra-pulmonares, e 3) anormalidades da oxigenação arterial (pressão parcial de oxigênio <70 mm Hg ou gradiente alvéolo-arterial de oxigênio >20 mm Hg). Sua freqüência varia de acordo com os métodos diagnósticos utilizados. OBJETIVOS: Fazer revisão da literatura sobre patogenia, diagnóstico e tratamento da síndrome hepatopulmonar. MÉTODOS: Levantamento no MEDLINE das publicações nacionais e internacionais mais relevantes sobre a síndrome hepatopulmonar. RESULTADOS: A prevalência da síndrome hepatopulmonar varia de 4% a 17,5%, a depender dos critérios diagnósticos utilizados. A doença hepática associada mais comum é a cirrose. O gradiente alvéolo-arterial de oxigênio parece ser o melhor parâmetro para avaliação das anormalidades da oxigenação arterial. Em relação à detecção das dilatações vasculares intra-pulmonares, a ecocardiografia com contraste é o método de escolha, pois é de fácil realização e pode diferenciar as comunicações intra-pulmonares das intra-cardíacas. No tratamento da síndrome hepatopulmonar, poucos relatos bem sucedidos puderam ser reproduzidos e confirmados utilizando terapia farmacológica e/ou radiologia intervencionista. Atualmente, o transplante de fígado é considerado a principal opção terapêutica desses pacientes, com resultados animadores. CONCLUSÕES: A síndrome hepatopulmonar é uma enfermidade freqüente. Exames gasométricos são necessários para o seu diagnóstico. O transplante de fígado é o tratamento de escolha para os portadores da síndrome.

Gas exchange mechanism of orthodeoxia in hepatopulmonary syndrome

The mechanism of orthodeoxia (OD), or decreased partial pressure of arterial oxygen (PaO2) from supine to upright, a characteristic feature of hepatopulmonary syndrome (HPS), has never been comprehensively elucidated. We therefore investigated the intrapulmonary (shunt and ventilation-perfusion [VA/Q] mismatching) and extrapulmonary factors governing PaO2 in 20 patients with mild to severe HPS (14 males, 6 females; 50 +/- 3 years old SE) at upright and supine, in random order. We set out a cutoff value for OD, namely a PaO2 decrease > or = 5% or > or = 4 mm Hg (area under the receiver operating characteristic curve, 0.96 each). Compared to supine, 5 patients showed OD (PaO2 change, -11% +/- 2%, -7 +/- 1 mm Hg, P < .05) with further VA/Q worsening (shunt + low VA/Q mode increased from 19% +/- 7% to 21% +/- 7% of cardiac output [QT], P < .05), as opposed to 15 patients who did not (+2% +/- 2%, +1+/- 1 mm Hg) with VA/Q improvement (from 20% +/- 4% to 16% +/- 4% of QT, P < .01). Cardiac output was significantly lower in OD patients in both positions. Changes in extrapulmonary factors at upright, such as increased minute ventilation and decreased QT, were of similar magnitude in both subsets of patients. In conclusion, our data suggest that gas exchange response to OD in HPS points to a more altered pulmonary vascular tone inducing heterogeneous blood flow redistribution to lung zones with prominent intrapulmonary vascular dilatations.

Hepatopulmonary Syndrome in HIV--Hepatitis C Virus Coinfection: A Case Report and Review of the Literature

A wide array of diagnoses must be considered when a patient with advanced liver disease and human immunodeficiency virus (HIV) infection presents with hypoxemia. It is important to entertain the possibility of hepatopulmonary syndrome (HPS) in such patients, a diagnosis that must be confirmed with a contrast-enhanced echocardiogram (bubble study). We describe a case of HPS diagnosed in a patient with HIV infection and chronic liver disease and review the literature on HPS.

Portopulmonary hypertension and hepatopulmonary syndrome

The clinically and pathophysiologically distinct entities of portopulmonary hypertension and hepatopulmonary syndrome occur in a substantial proportion of patients who have advanced liver disease of different causes. These disorders are notoriously underdiagnosed, but they have a substantial impact on survival and require focused treatment. Abnormal intrapulmonary vascular dilatation, the hallmark of hepatopulmonary syndrome, can cause profound hypoxaemia that can be very difficult to treat. By contrast, portopulmonary hypertension results from excessive pulmonary vasoconstriction and vascular remodelling that eventually leads to right-heart failure. Insights into the pathogeneses of these syndromes have led to novel therapeutic approaches. However, in severely affected patients, effective treatment remains a difficult task. In selected patients, liver transplantation represents the only treatment option, but the decision to do isolated liver transplantation is particularly challenging in patients who have severe pulmonary disease involvement. Data from several centres have contributed to provide criteria that allow improved prediction of which patients may, or may not, benefit from liver transplantation alone.

Hepatopulmonary syndrome after living donor liver transplantation and deceased donor liver transplantation: a single-center experience

Hepatopulmonary syndrome (HPS) is a progressive, debilitating complication of end-stage liver disease. In contrast to the well-established reversal of HPS after deceased donor liver transplantation (DDLT), little has been written about the natural course of HPS after the newer procedure of living donor liver transplantation (LDLT). We describe HPS in a small series of 4 liver transplant recipients (2 DDLT; 2 LDLT) at a single center. Before transplantation, these 4 patients had a mean shunt fraction of 23.6 +/- 14.3% and a mean PaO2 of 58.5 +/- 11.3 mm Hg. All 4 patients used supplemental oxygen before transplantation. Sixteen weeks after transplantation, all 4 patients had normalized or improved shunt fraction and PaO2. These patients regained normal pulmonary function within a few months, despite the period of hepatic regeneration after LDLT. In conclusion, both DDLT and LDLT are associated with rapid and dramatic reversal of HPS.

Frequency, clinical characteristics, and respiratory parameters of hepatopulmonary syndrome

OBJECTIVES

To determine the frequency and the clinical characteristics of hepatopulmonary syndrome (HPS) in cirrhotic candidates for orthotopic liver transplantation and to identify the major respiratory parameters predictive of the presence of changes in arterial oxygenation.

PATIENTS AND METHODS

Patients underwent transthoracic contrast-enhanced echocardiography, pulmonary scintigraphy, pulmonary function test with diffusing capacity of lung for carbon monoxide (DLCO), and measurement of arterial blood gases.

RESULTS

Fifty-six patients were studied. Twenty-five patients (45%) presented with intrapulmonary vascular dilatations, but only 9 (16%) fulfilled the criteria for HPS. The clinical or demographic characteristics considered did not differ in the patients with and without HPS. The DLCO value was significantly lower in patients with HPS (P=.01). However, 32 (80%) of 40 patients with low DLCO values did not fulfill the criteria for HPS. An alveolar arterial oxygen gradient (AaPO2) of more than 20 mm Hg showed a higher diagnostic accuracy (91%) in the assessment of HPS than did the DLCO of less than 80% predicted (41%) and the AaPO2 of more than 15 mm Hg (71%).

CONCLUSIONS

The AaPO2 proved to be a more reliable index than PaO2 and DLCO for the determination of changes in arterial oxygenation in HPS. The DLCO does not seem to be a good marker for HPS screening. Intrapulmonary vascular dilatations were frequent, even in patients who did not fulfill the criteria for HPS.

Liver transplantation for hepatopulmonary syndrome: a ten-year experience in Paris, France

BACKGROUND

Although the possibility of reversing hepatopulmonary syndrome (HPS) after liver transplantation is now well established, the proportion of patients in whom reversibility is observed and the time to resolution of HPS remain uncertain.

METHODS

We analyzed the outcome of all adult patients with HPS who underwent orthotopic liver transplantation in all the liver transplant centers in Paris, during a 10-year period.

RESULTS

Twenty-three adult patients (median age, 47 years; range, 14-64) underwent transplantation in four institutions. Median PaO(2) was 52 (range, 32-67) mm Hg and median alveolar-arterial oxygen gradient was 66 mm Hg. When patients were breathing 100% O(2), median PaO(2) was 310 (range, 74-663) mm Hg. Median isotopic shunt ratio was 33% (range, 0-80%). The overall mortality during the study period was 30.5% (7/23). Perioperative mortality was 8.5%, whereas late mortality was 22%. None of the preoperative characteristics of HPS (isotopic shunt ratio, PaO(2) on room air or on 100% oxygen) was associated with overall postoperative mortality. Of the 21 patients surviving the perioperative period (median follow-up, 17 months; range, 0.5-72), a decrease in alveolar-arterial oxygen gradient of at least 5 mm Hg and at least 10 mm Hg was observed in 21 of 21 and in 18 of 21 patients, respectively, with great variations in the time of improvement. The threshold of 70 mm Hg was reached in 15 patients. The lower the preoperative PaO(2), the longer the time to reach this point.

CONCLUSION

Our data strongly support the role of orthotopic liver transplantation in adult patients with HPS, regardless of its severity.

Liver Transplantation for Cholestatic Liver Disease

Liver transplantation is an effective form of therapy for patients with end-stage cholestatic disease that improves both survival and quality of life. Liver transplantation is very effective for the treatment of intractable pruritus but less effective for the treatment of lethargy. Survival rates are good (more than 70% at 5 years); these patients are at greater risk of developing acute and chronic rejection and are more likely to require long-term immunosuppression. Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) recur in the graft. Recurrent PSC may be difficult to differentiate from secondary sclerosing cholangitis, but it recurs in up to 60% of patients at 5 years and may reduce graft survival. PBC recurrence, noted in up to 40% of patients at 10 years, has little effect on graft survival with respect to cancers. Patients with PSC are at greater risk of both colonic cancer (which may be reduced by ursodeoxycholic acid) and cholangiocarcinoma. Diagnosis of cholangiocarcinoma before transplantation usually contraindicates transplantation. The main challenges facing liver transplantation are the need to expand the donor pool and the need to find immunosuppressive regimens with fewer long-term toxicities.

Prospective evaluation of outcomes and predictors of mortality in patients with hepatopulmonary syndrome undergoing liver transplantation

The hepatopulmonary syndrome (HPS) occurs in a subgroup of patients with cirrhosis and results from intrapulmonary vasodilatation, which may cause significant hypoxemia. Liver transplantation has emerged as a therapeutic option for patients with HPS based on retrospective case series and reports. However, morbidity and mortality appear to be increased after transplantation for HPS, and no prospective studies evaluating clinical features that may predict poor surgical outcome are available. Therefore, we prospectively evaluated the utility of the degree of hypoxemia, the arterial oxygen response to 100% oxygen administration, and the macroaggregated albumin (MAA) scan quantification of intrapulmonary shunting as predictors for outcome after liver transplantation. Our cohort consisted of 24 patients with cirrhosis and HPS who underwent liver transplantation over a 5-year period at 2 transplant centers who were followed at least 1 year after transplantation. All patients underwent preoperative evaluation for HPS with standardized methods. Seven patients (29%) died postoperatively, 5 of cardiorespiratory complications. All deaths occurred within 10 weeks after transplantation. A preoperative arterial oxygen tension (PaO(2)) of </= 50 mm Hg alone or in combination with a MAA shunt fraction >/= 20% were the strongest predictors of postoperative mortality. In conclusion, we found that mortality is increased after liver transplantation for HPS, particularly in patients with more severe hypoxemia and significant intrapulmonary shunting. Preoperative testing for the severity of HPS can be used to stratify patients according to the risk for postoperative mortality.

Pulmonary gas exchange abnormalities in liver transplant candidates

Abnormal diffusing capacity is the commonest pulmonary dysfunction in liver transplant candidates, but severe hypoxemia secondary to hepatopulmonary syndrome and significant pulmonary hypertension are pulmonary vascular manifestations of cirrhosis that may affect the perioperative course. We prospectively assessed the extent of pulmonary dysfunction in patients referred for liver transplantation. A total of 57 consecutive patients with chronic liver disease were evaluated. All patients had a chest radiograph, standing arterial blood gas on room air, pulmonary function testing, and Doppler echocardiogram. Those patients with arterial hypoxaemia (PaO(2) < 10 kPa) also underwent (99m)Tc-macroaggregated albumin lung scan, and nine patients had agitated normal saline injection during echocardiography to define further the existence of pulmonary vascular dilatation. Reduced diffusing capacity for carbon monoxide less than 75% of the predicted value was found in 29 of 57 (51%) patients. Although elevated alveolar-arterial oxygen tension difference was detected in 35% (20/57) of the patients, only four (7%) patients had hypoxemia. We were unable to find evidence of intrapulmonary vascular dilatation either on the lung scan or saline-enhanced echocardiography in any of these patients. Reduction in diffusing capacity for carbon monoxide was noted in 75% (18/24) of patients who were transplanted for primary biliary cirrhosis and was accompanied by widened alveolar-arterial oxygen tension in 10 out of 18 (56%) of patients. This study shows that in liver transplant candidates, diffusion impairment and widened alveolar-arterial oxygen tension difference were frequently detected, especially in patients with primary biliary cirrhosis.

Update on ascites and hepatorenal syndrome

Ascites is the most common complication occurring during liver cirrhosis. Even if a significant decrease in renal clearance may be observed in the first step of chronic active liver disease, renal impairment, at times complicated by the typical signs of hepatorenal syndrome, occurs only in patients with ascites, especially when tense and refractory. Experimental and clinical data seem to suggest a primary sodium and water retention in the pathogenesis of ascites, in the presence of an intrahepatic increase of hydrostatic pressure, which, by itself, physiologically occurs during digestion. Abnormal sodium and water handling leads to plasma volume expansion, followed by decreased peripheral vascular resistance and increased cardiac output. This second step is in agreement with the peripheral arterial vasodilation hypothesis, depicted by an increase in total blood volume, but with a decreased effective arterial blood volume. This discrepancy leads to the activation of the sympathetic nervous and renin-angiotensin-aldosterone systems associated with the progressive activation of the renal autacoid systems, especially, that of the arachidonic acid. During advanced cirrhosis, renal impairment becomes more sustained and renal autacoid vasodilating substances are less available, possibly due to a progressive exhaustion of these systems. At the same time ascites becomes refractory inasmuch as it is no longer responsive to diuretic treatment. Various pathogenetic mechanisms leading to refractory ascites are mentioned. Finally, several treatment approaches to overcome the reduced effectiveness of diuretic therapy are cited. Paracentesis, together with simultaneous administration of human albumin or other plasma expanders is the main common approach to treat refractory ascites and to avoid a further decrease in renal failure. Other effective tools are: administration of terlipressin together with albumin, implantation of the Le Veen shunt, surgical porto-systemic shunting or transjugular intrahepatic portosystemic stent-shunt, or orthotopic liver transplantation, according to the conditions of the individual patient.

Pulmonary dysfunction in non-cirrhotic patients with chronic viral hepatitis

Background: Hepatopulmonary syndrome (HPS), defined as hypoxemia and functional intrapulmonary right-to-left shunts in the presence of chronic liver disease, is a frequent complication of end-stage liver disease. The aim of this study was to determine the extent of pulmonary dysfunction and the prevalence of HPS in non-cirrhotic patients with chronic viral hepatitis. Methods: Lung function tests were carried out in 178 patients with chronic viral hepatitis (mean age 43.2 years, 95 smokers). To demonstrate intrapulmonary shunting, contrast echocardiography was performed in all patients with hypoxemia (paO(2)<70 mmHg) or a reduced diffusion capacity (DLCO<70% predicted). Results: The median results of lung function parameters (FVC, FEV(1), FEV(1)/FVC, TLC, DLCO, and blood gas analysis) were normal. Despite normal lung function, hypoxemia and/or DLCO reduction were observed in 17 of 178 patients (9.6%). A correlation with inflammatory activity, extent of fibrosis, or etiology was not found. Intrapulmonary shunting was observed in three of 17 patients. Two of these patients fulfilled the diagnostic criteria of HPS. Conclusions: Impaired gas exchange is a common finding even in non-cirrhotic patients with chronic viral hepatitis. HPS, however, was present in 1.1% of patients with chronic viral hepatitis and is thus not restricted to patients with liver cirrhosis, portal hypertension, or acute liver failure.